Scaling properties of energy spreading in nonlinear Hamiltonian two-dimensional lattices

In nonlinear disordered Hamiltonian lattices, where there are no propagating phonons, the spreading of energy is of subdiffusive nature. Recently, the universality class of the subdiffusive spreading according to the nonlinear diffusion equation (NDE) has been suggested and checked for one-dimensional lattices. Here, we apply this approach to two-dimensional strongly nonlinear lattices and find a nice agreement of the scaling predicted from the NDE with the spreading results from extensive numerical studies. Moreover, we show that the scaling works also for regular lattices with strongly nonlinear coupling, for which the scaling exponent is estimated analytically. This shows that the process of chaotic diffusion in such lattices does not require disorder.Comment: 7 pages, 7 figure

Disorder Screening in Strongly Correlated Systems

Electron-electron interactions generally reduce the low temperature resistivity due to the screening of the impurity potential by the electron gas. In the weak-coupling limit, the magnitude of this screening effect is determined by the thermodynamic compressibility which is proportional to the inverse screening length. We show that when strong correlations are present, although the compressibility is reduced, the screening effect is nevertheless strongly enhanced. This phenomenon is traced to the same non-perturbative Kondo-like processes that lead to strong mass enhancements, but which are absent in weak coupling approaches. We predict metallicity to be strongly stabilized in an intermediate regime where the interactions and the disorder are of comparable magnitude.Comment: 4+epsilon pages, 3 figure

Formation of three-particle clusters in hetero-junctions and MOSFET structures

A novel interaction mechanism in MOSFET structures and $GaAs/AlGaAs$ hetero-junctions between the zone electrons of the two-dimensional (2D) gas and the charged traps on the insulator side is considered. By applying a canonical transformation, off-diagonal terms in the Hamiltonian due to the trapped level subsystem are excluded. This yields an effective three-particle attractive interaction as well as a pairing interaction inside the 2D electronic band. A type of Bethe- Goldstone equation for three particles is studied to clarify the character of the binding and the energy of the three-particle bound states. The results are used to offer a possible explanation of the Metal-Insulator transition recently observed in MOSFET and hetero-junctions.Comment: 4 page

Cauchy-perturbative matching and outer boundary conditions: computational studies

We present results from a new technique which allows extraction of gravitational radiation information from a generic three-dimensional numerical relativity code and provides stable outer boundary conditions. In our approach we match the solution of a Cauchy evolution of the nonlinear Einstein field equations to a set of one-dimensional linear equations obtained through perturbation techniques over a curved background. We discuss the validity of this approach in the case of linear and mildly nonlinear gravitational waves and show how a numerical module developed for this purpose is able to provide an accurate and numerically convergent description of the gravitational wave propagation and a stable numerical evolution.Comment: 20 pages, RevTe

Mathematical wind profiles

Augmented Fourier polynomials for mathematical representation of vertical profiles for horizontal wind velocitie

Cauchy-perturbative matching and outer boundary conditions I: Methods and tests

We present a new method of extracting gravitational radiation from three-dimensional numerical relativity codes and providing outer boundary conditions. Our approach matches the solution of a Cauchy evolution of Einstein's equations to a set of one-dimensional linear wave equations on a curved background. We illustrate the mathematical properties of our approach and discuss a numerical module we have constructed for this purpose. This module implements the perturbative matching approach in connection with a generic three-dimensional numerical relativity simulation. Tests of its accuracy and second-order convergence are presented with analytic linear wave data.Comment: 13 pages, 6 figures, RevTe

Interaction corrections to the Hall coefficient at intermediate temperatures

We investigate the effect of electron-electron interaction on the temperature dependence of the Hall coefficient of 2D electron gas at arbitrary relation between the temperature $T$ and the elastic mean-free time $\tau$. At small temperature $T\tau \ll \hbar$ we reproduce the known relation between the logarithmic temperature dependences of the Hall coefficient and of the longitudinal conductivity. At higher temperatures, this relation is violated quite rapidly; correction to the Hall coefficient becomes $\propto 1/T$ whereas the longitudinal conductivity becomes linear in temperature.Comment: 4 pages, 3 .eps figure

Life under Siege: The Jews of Magdeburg under Nazi Rule

This regional study documents the life and the destruction of the Jewish community of Magdeburg, in the Prussian province of Saxony, between 1933 and 1945. As this is the first comprehensive and academic study of this community during the Nazi period, it has contributed to both the regional historiography of German Jewry and the historiography of the Shoah in Germany. In both respects it affords a further understanding of Jewish life in Nazi Germany. Commencing this study at the beginning of 1933 enables a comprehensive view to emerge of the community as it was on the eve of the Nazi assault. The study then analyses the spiralling events that led to its eventual destruction. The story of the Magdeburg Jewish community in both the public and private domains has been explored from the Nazi accession to power in 1933 up until April 1945, when only a handful of Jews in the city witnessed liberation. This study has combined both archival material and oral history to reconstruct the period. Secondary literature has largely been incorporated and used in a comparative sense and as reference material. This study has interpreted and viewed the period from an essentially Jewish perspective. That is to say, in documenting the experiences of the Jews of Magdeburg, this study has focused almost exclusively on how this population simultaneously lived and grappled with the deteriorating situation. Much attention has been placed on how it reacted and responded at key junctures in the processes of disenfranchisement, exclusion and finally destruction. This discussion also includes how and why Jews reached decisions to abandon their Heimat and what their experiences with departure were. In the final chapter of the community’s story, an exploration has been made of how the majority of those Jews who remained endured the final years of humiliation and stigmatisation. All but a few perished once the implementation of the ‘Final Solution’ reached Magdeburg in April 1942. The epilogue of this study charts the experiences of those who remained in the city, some of whom survived to tell their story

Life under siege: the jews of Magdeburg under Nazi rule

This regional study documents the life and the destruction of the Jewish community of Magdeburg, in the Prussian province of Saxony, between 1933 and 1945. As this is the first comprehensive and academic study of this community during the Nazi period, it has contributed to both the regional historiography of German Jewry and the historiography of the Shoah in Germany. In both respects it affords a further understanding of Jewish life in Nazi Germany. Commencing this study at the beginning of 1933 enables a comprehensive view to emerge of the community as it was on the eve of the Nazi assault. The study then analyses the spiralling events that led to its eventual destruction. The story of the Magdeburg Jewish community in both the public and private domains has been explored from the Nazi accession to power in 1933 up until April 1945, when only a handful of Jews in the city witnessed liberation. This study has combined both archival material and oral history to reconstruct the period. Secondary literature has largely been incorporated and used in a comparative sense and as reference material. This study has interpreted and viewed the period from an essentially Jewish perspective. That is to say, in documenting the experiences of the Jews of Magdeburg, this study has focused almost exclusively on how this population simultaneously lived and grappled with the deteriorating situation. Much attention has been placed on how it reacted and responded at key junctures in the processes of disenfranchisement, exclusion and finally destruction. This discussion also includes how and why Jews reached decisions to abandon their Heimat and what their experiences with departure were. In the final chapter of the community’s story, an exploration has been made of how the majority of those Jews who remained endured the final years of humiliation and stigmatisation. All but a few perished once the implementation of the ‘Final Solution’ reached Magdeburg in April 1942. The epilogue of this study charts the experiences of those who remained in the city, some of whom survived to tell their story

Critical behavior at Mott-Anderson transition: a TMT-DMFT perspective

We present a detailed analysis of the critical behavior close to the Mott-Anderson transition. Our findings are based on a combination of numerical and analytical results obtained within the framework of Typical-Medium Theory (TMT-DMFT) - the simplest extension of dynamical mean field theory (DMFT) capable of incorporating Anderson localization effects. By making use of previous scaling studies of Anderson impurity models close to the metal-insulator transition, we solve this problem analytically and reveal the dependence of the critical behavior on the particle-hole symmetry. Our main result is that, for sufficiently strong disorder, the Mott-Anderson transition is characterized by a precisely defined two-fluid behavior, in which only a fraction of the electrons undergo a "site selective" Mott localization; the rest become Anderson-localized quasiparticles.Comment: 4+ pages, 4 figures, v2: minor changes, accepted for publication in Phys. Rev. Let